Government and employers are increasingly aware of the need for protecting the health and safety of workers. For this reason, it is common to find eye wash fountains at industrial work stations, laboratories, and other locations where workers are exposed to gaseous fumes, liquids or solid materials which can irritate or injure eyes upon contact therewith. The Occupational Safety and Health Administration (OSHA) has made eye wash fountains mandatory for particular industrial work stations.
Some prior art devices have employed eye wash fountains providing sprays of water from regular plant plumbing connections. Other prior art devices, such as the eye wash fountains disclosed in U.S. Pat. No. 4,012,798 to Liautaud and U.S. Pat. No. 4,363,146 to Liautaud, are self-contained, gravity-fed, and independent of any plumbing connections. Such eye wash fountains typically contain a reservoir (or bottle) of wash fluid spaced above two opposed liquid spray nozzles. Upon activating the fluid flow, the wash fluid from the reservoir is fed solely by gravity to the nozzles to cause a gravity-induced spray of wash fluid from the nozzles.
In an effort to encourage suitable eye wash facilities, the American National Standards Institute (ANSI) has promulgated voluntary standards for portable eye wash fountains relating to flushing periods and the rate of flow of wash fluid. These standards dictate that portable eye wash fountains should deliver no less than 0.4 gallons per minute (1.5 liters per minute) of eye wash fluid for a time period of 15 minutes.
A drawback of the gravity-fed eye wash fountains of the type described above is that they contain fluid significantly in excess of the amount required for actual flushing to meet the ANSI standards because the rate of flow of wash fluid from the gravity-fed eye wash fountains decreases over time. The reason for this decrease in fluid flow rate over time is that the fluid head height in the reservoir decreases as the wash fluid is dispensed from the nozzles, thereby decreasing the amount of hydraulic pressure on the wash fluid over time. This reduction in hydraulic pressure over time causes a corresponding decrease in the fluid flow rate. To provide 0.4 gallons per minute of wash fluid for a full 15 minutes, the reservoirs of gravity-fed eye wash fountains must hold a sufficient amount of eye wash fluid that the fluid flow rate does not drop below 0.4 gallons per minute prior to 15 minutes from activation.
Another drawback of the gravity-fed portable eye wash fountains is that the rate of flow of wash fluid is not constant, but rather changes over time. The fluid flow rate is initially quite high so that the fluid flow rate does not drop below 0.4 gallons per minute after 15 minutes. The changes in fluid flow rate can limit effective flushing.
A further drawback of gravity-fed portable eye wash fountains is they often waste much of the wash fluid in the reservoir (as much as 30 percent of the initial supply) because there is insufficient hydraulic pressure to force all of the wash fluid from the reservoir through the nozzles. The flow of wash fluid through the nozzles substantially stops after only a portion of the wash fluid in the reservoir has been dispensed from the nozzles.
Yet another drawback of existing eye wash fountains is that they do not maintain the stability of the wash fluid in the reservoir for extended periods of time and, as a result, the wash fluid must be replaced with fresh wash fluid at fairly short time intervals. The fluid delivery systems of existing eye wash fountains generally require some exposure of the wash fluid in the reservoir to air. This exposure to air improves the flow of the wash fluid through the nozzles. At the same time, the exposure to air encourages the growth of bacteria existing in the wash fluid and the eye wash fountains themselves. The wash fluid in these eye wash fountains is stagnant, and at ambient temperature the environment is conducive to the growth of micro-organism populations. With this growth of bacteria, the wash fluid typically must be replaced with fresh wash fluid at least every six months, even when treated with preservatives. Further, most existing eye wash fountains employ tap water which contains chemical and solid particle contaminants such as chlorine, lead, and rust. The replacement of wash fluid is time-consuming and expensive in terms of both labor and materials.
Yet a further drawback of existing eye wash fountains is that the wash fluid dispensed from the nozzles generally is drained onto the floor, resulting in a mess which must be cleaned up. Alternatively, the used eye wash fluid is drained into an extra floor-standing container separate from the eye wash fountain. The extra container, in combination with the eye wash fountain, occupies a large amount of space.
An additional drawback of existing eye wash fountains is that the eye wash fountains typically must be removed from their operating position for draining of unused wash fluid, cleaning, and refilling with fresh wash fluid. Such removal of the eye wash fountains from their operating position is burdensome and time-consuming. When refilled and ready to be returned to their operating position, the units often weigh in excess of 130 pounds.
A need therefore exists for a self-contained eye wash station which overcomes the aforementioned shortcomings associated with existing portable eye wash fountains.